The present invention relates generally to a phosphate cement composition, and more particularly to a phosphate cement composition that cures rapidly, and is flame and heat resistant.
Cementious materials are used extensively in the construction industry for such uses as roadways, bridges, pools, walls, tunnels, and other structures which are exposed to the elements and need to maintain their strength. Portland cement has traditionally been the cement of choice. It is typically a mixture of water, calcined lime and silica. It is cheap to produce, easy to handle. There are, however, several disadvantages to Portland cement. Source materials often have inconsistent quality. Portland cement is often highly viscous which is acceptable for pouring and spreading, but is a major disadvantage if pumping or spraying is desired. Portland cement also has a slow cure rate.
Inasmuch as many applications require rapid curing without adversely affecting strength or other physical properties, there is a need for rapid curing cement compositions. Examples of previous attempts to provide such a rapid curing cement are provided in U.S. Pat. Nos. 3,879,209, 3,960,580, 5,002,610, and 6,136,088. There; however, remains a need for a cement composition that is rapidly curable and does not adversely affect physical properties like chemical stability, strength, corrosion, and the like.
An alternative to Portland cement is phosphate cement. Phosphate cement typically comprises an acid component such as phosphoric acid or an alkaline earth phosphate salt (e.g., magnesium phosphate), and a base component such as magnesium oxide. Phosphate cements tend to cure rapidly, and have excellent chemical stability and compressive strength.